Recovering What Breaks in a Trapped-Ion Quantum Simulation of a Lattice Gauge Theory

Abstract

A recent trapped-ion experiment realised a lattice gauge theory with the gauge field in the internal states of the ions and bosonic matter in their vibrations. We showed earlier that its noise damage can be predicted. Here, we show that most of it can be undone. The conservation law of the theory is a parity of each vibrational mode, which heating flips, so a heating event leaves a mark that can be read without disturbing the physics. We keep only the runs in which this mark never changed. With equal heating rates and continuous monitoring, the kept runs reproduce the heating-free dynamics exactly, with a closed-form yield. Reading the mark at finite intervals introduces a small bias linear in the interval, which we derive and bound. At the reported rates, a single final check removes most of the heating and preparation damage while accepting eight runs out of ten.